In OFDM (Orthogonal Frequency Division Multiplex) transmission, as shown in FIG. 1, there are cases where communication quality of each subcarrier block (SCB1 to SCB8) is different from one another due to frequency selective fading. Further, in downlink OFDM transmission, channel states vary for each communication terminal apparatus (UE), and so, by making each communication terminal apparatus report the received quality to the base station apparatus (Node B), the base station apparatus can select per communication terminal apparatus only subcarriers having good received quality and allocate transmission data. This method is called frequency scheduling. In general, to perform frequency scheduling, it is necessary that each communication terminal apparatus measures received quality for a known pilot signal transmitted from Node B, and reports received quality information (CQI) based on the measurement result to the base station apparatus. However, when the number of subcarriers forming an OFDM signal is large, the report amount is enormous when the received quality is reported for all subcarriers, and there is a problem that uplink wireless resources are wasted.
For the above-mentioned problem, various reporting amount reducing schemes have been proposed. For example, such a method is known that a communication terminal apparatus does not report received quality of a subcarrier with poor quality, and only reports received quality of a subcarrier with good quality (for example, Patent Document 1)
Patent Document 1: Japanese Patent Application Laid-Open No. 2001-351971